Radar means technology that detects an object using electromagnetic (EM) scattering and the range, speed, and shape of the object. In other words, a radar transceiver detects reflection wave signals backscattered from an object and calculates a radar cross section (RCS) of the object based on the signal strength of the reflection wave signals. The RCS is a parameter indicating how big a target object is seen on a radar and varies depending on the dielectric constant, shape, angle, and frequency of the target object.
Typical EM radar imaging has been developed and used for purposes of distance measurement, targeting, and tracking. The size in which a radar is mounted may reach a few meters. Since several years ago, communication systems using millimeter waves (mmWave) with a frequency of 30 GHz or more and a wavelength of 1 cm or less have been researched, leading to the implementation of 1 cm or less-sized micro antennas. Such micro antennas happened to be equipped in a transceiver, allowing for implementations of tiny semiconductor chip-type radars and various applications using the same.
In developing an application technology using short-range mmWave radar, it is critical to compensate for the strength of reflection wave signals intended for calculating a RCS (hereinafter, simply “reflection signal strength”). More particularly, 1 m-long or less short-range radars may be subject to a distortion of reflection wave signals by the maximum-minimum distance difference between the radar and the target. A signal attenuation in a radar system is proportional to the power of four. Thus, a slight difference in the maximum-minimum difference may cause a significant distortion of a radar image within a short range. Such issue could be disregarded given the fact that radar systems according to the related art have mostly accounted for long-distance object detection because the maximum-minimum distance difference relative to the distance to the target is neglectably small. For example, when the distance between a radar and a target is a few tens of km, and the size of the object is several meters, the object would be seen like a dot when viewed from the radar. However, if a short-range radar, a few tens of cm away from a target object looks at a few centimeter size object, the difference in strength between signals reflected on the same surface of an object needs to be compensated due to the difference in strength between the earliest reflection signal coming from the object and the latest coming reflection signal.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.